The invention relates to a method for forming a liquid crystal display, and in particular to a method for forming a reflective liquid crystal display.
Liquid crystal display (LCD) devices, widely used in devices such as portable televisions and notebook computers, are classified into transmission types using a backlight as a light source, and reflective types using an external light source, such as sunlight or indoor lamp. It is difficult to decrease the weight, volume, and power consumption of transmission types due to the power requirements of the backlight component. While reflective types have the advantage of not requiring a backlight component, but they cannot operate without an external light source.
In order to overcome the drawbacks of these two types of LCDs, a transflective LCD device which can operate as both a reflective and transmission type LCD is disclosed. The transflective LCD device has a reflective electrode in a pixel region, having a transmissive portion. Thus, the transflective LCD device has lower power consumption than the conventional transmission type LCD device since no backlight component is required in the presence of bright external light. Further, in comparison with the reflective type LCD device, the transflective LCD device has the advantage of operating as a transmission type LCD device using a backlight when no external light is available.
FIG. 1 is a plan view of a conventional transflective LCD. In a conventional transflective LCD, an isolation layer 110 is disposed on a bottom substrate 100, and a pixel area 165 overlies the isolation layer 110. A top substrate 160 is opposite the bottom substrate 100. A color filter 150 is disposed on the inner side of the top substrate 160. A common electrode 140 is disposed on the color filter 150. A liquid crystal layer 130 is interposed between the bottom substrate 100 and the top substrate 160. A reflective layer 120 is disposed on outer side of the bottom substrate 100, one portion of which reflects ambient light and another passes source light of a LCD device.
During operation, however, due to refraction, reflective light and incident light 170 may not pass through the same pixel 165, thus generating aberration problem. One solution is to form the reflective electrode on the inner side of the bottom electrode. This technology, however, requires at least six lithography steps, increasing complexity and cost.